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AccurAPM Module

Fitness-For-Service (FFS) to API 579-1/ASME FFS-1

Decide whether damaged equipment can stay in service — and prove it.

AccurAPM FFS runs a fitness for service assessment of in-service pressure vessels, piping, storage tanks, boiler components and fired heater tubes to API 579-1/ASME FFS-1, 2021 Edition. It implements Level 1 and Level 2 assessments in full across the damage types of Parts 3 through 14, and prepares the load cases and acceptance criteria a Level 3 numerical analysis needs. Every assessment returns a verdict, a reduced rating where one is required, a remaining life and a next inspection date — with the equations, clause references and reviewers recorded alongside.

API 579-1

ASME FFS-1, 2021 Edition

Parts 3–14

Twelve damage types

Traceable

Equation-level audit record

Request an FFS Demo All modules

An AccurAPM Fitness-For-Service assessment on a laptop: thickness readings entered as points, inputs validated, and a result of Acceptable with an RSF of 1.1195 by API 579, alongside the recalculated MAWP and the next inspection date.

Capabilities

Key capabilities

✓Level 1 and Level 2 assessments implemented in full for every damage type in Parts 3 through 14.

✓Level 3 support by exporting a defined load case set and importing linearised stress results from your FEA package.

✓Computes the reduced MAWP or maximum fill height where a flaw is not acceptable at the current rating.

✓Remaining life and a recommended next inspection date on every assessment.

✓Long-term and short-term corrosion rates from thickness history, without re-entering readings.

✓Imports thickness grids and profiles, including scanned UT (C-scan) reductions and laser profilometry as a gridded thickness matrix.

✓Both US Customary and SI units, with symbols following the Standard's nomenclature.

✓Flaw interaction and multi-damage handling where more than one damage type applies to a component.

✓A complete, reproducible record: every input, intermediate quantity, equation applied and clause reference, with named analyst and reviewer.

✓Amended inspection records flag affected released assessments for review, rather than silently recalculating them.

Coverage

The damage types it assesses

Parts 3 through 14 of API 579-1/ASME FFS-1. Parts 1 and 2 govern scope, responsibilities and documentation, which the module applies throughout.

3Brittle fracture

4General metal loss

5Local metal loss

6Pitting corrosion

7Hydrogen blisters, HIC and SOHIC

8Weld misalignment and shell distortions

9Crack-like flaws

10Creep damage and remaining life

11Fire damage

12Dents, gouges and dent-gouge combinations

13Laminations

14Fatigue

Assessment levels

Three levels, and what each one asks of you

A higher level always overrides a lower one for the same flaw and inspection date, and both results stay in the record.

Level 1

Conservative screening on minimal inspection data, with no stress analysis — performed by an inspector or plant engineer. A pass means fit for service. A fail means escalate, not condemn.

Level 2

Detailed but still closed-form, requiring thickness profiles or full flaw characterisation — performed by a pressure-equipment engineer. Usually less conservative, and more permissive, than Level 1.

Level 3

Numerical analysis by a specialist, used where Levels 1 and 2 fail or do not apply. AccurAPM exports the defined load case set and imports the linearised stress results; the FEA itself runs in your analysis package.

Questions

Fitness-For-Service: common questions

What is a Fitness-For-Service assessment?

A Fitness-For-Service (FFS) assessment is a quantitative engineering evaluation, to API 579-1/ASME FFS-1, of whether equipment with a known flaw or damage can continue to operate safely, and for how long. It gives a remaining life, a reduced MAWP where needed, and a run, repair or replace decision backed by a traceable calculation.

Which parts of API 579-1/ASME FFS-1 does AccurAPM cover?

Level 1 and Level 2 assessments in full across Parts 3 to 14 of the 2021 Edition, covering metal loss, crack-like flaws, dents and the other damage types the standard defines. For Level 3, AccurAPM exports the defined load case set and imports the linearised stress results; the numerical analysis itself runs in your FEA package.

Where does the thickness data for an FFS assessment come from?

From the inspection data management system (IDMS) in the same platform. CML thickness history, corrosion rates and remaining life flow into the FFS module without re-entry, and the result feeds back into risk-based inspection, with any rerate governed by management of change.

Does the FFS result change the inspection interval?

When the FFS remaining life is shorter than the RBI-derived interval, the FFS result governs, and the next inspection date updates accordingly.

Outcomes

Business value

✓Keep serviceable equipment in service. A quantified assessment against the Standard replaces a conservative guess, and often avoids an unnecessary repair or replacement.
✓A failed assessment is never a condemnation. Every result offers the four dispositions the Standard permits — escalate to the next level, rerate to a reduced MAWP or temperature, remediate and re-assess, or repair, replace or retire.
✓Defensible in an audit. Each number traces to the clause that mandates it, so a reviewer can follow the calculation rather than take it on trust.
✓No double entry. Thickness history arrives from inspection data management, and operating history from the process historian.
✓Rerating stays governed. A rerate raises a management-of-change item; the equipment rating does not move until that change is approved.
✓Engineering judgement is preserved. The module evaluates the flaw types you have identified — it does not select damage mechanisms for you, and every assessment is released under a named engineer.

How it connects

Connected workflow

An FFS assessment is direct evidence about a component's condition, which makes it more informative than a generic damage-factor model. Where FFS establishes a remaining life shorter than the RBI-derived interval, the FFS result governs — and AccurAPM raises that conflict explicitly rather than letting the two subsystems disagree quietly.

Put a Number on Damaged Equipment

Bring us a real flaw — metal loss, a crack-like indication, a dent, creep service — and we will walk through the assessment as AccurAPM performs it.

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